<div style="height: 100%; display: flex; flex-direction: column">
    <p style="flex: 0 1 0%">
        <label>Dark mode: <input type="checkbox" onchange="setDarkMode(this.checked)" /></label>
    </p>
    <div style="flex: 1 1 0%"><div id="myGrid" style="height: 100%"></div></div>
</div>
